1. Field of the Invention
The present invention relates to a guideline of an electromagnetic surface wave and a device for detecting an object using the guideline, and more particularly to a device suitable for the use of detecting entry of various objects including human beings and animals into a specific area in a field of construction, stock-farming, agriculture or the like, for the purpose of prevention of crimes or the like.
2. Description of the Prior Art
A device for detecting an object entering into a specific area using infrared rays or supersonic waves has been heretofore known as a device for detecting an object. Such a conventional detecting device has a drawback that signals are dispersed and detection thereof over such a long distance that exceeds 10 m is difficult since infrared signals or supersonic signals are radiated into space, and no device that can be used in the fields of construction, stock-farming and agriculture, etc. in particular could not be found in the fields of utilization mentioned above.
Accordingly, such an idea has been hit upon that an electromagnetic surface wave guideline is used as means for transmitting signals in a range exceeding 10 m by controlling diffusion off the signals, and a phenomenon that is generated by a fact that the object approaches or comes into contact with the electromagnetic surface wave guideline is detected. A Goubau line such as shown in FIG. 5 has been heretofore known as such a surface wave guideline. The Goubau line has a structure that a conductor wire portion 52 such as copper is covered with a dielectric 51 such as plastic or enamel, and has been once applied in common viewing of television or the like. Further, a surface wave guideline having such a periodic structure as shown in FIG. 6 is also known, in which periodic structural portions 61 and a ground plate portion 62 are formed by pressing a sheet metal such as aluminum, and is used when it is installed on the ground for transmitting the surface wave.